DNA from maggot guts used to identify corpse in criminal case

Body was so badly burned that collecting DNA samples was impossible.

A team of pathologists has published a paper revealing how, for the first time, crime investigators identified the body of a burn victim by conducting a DNA analysis of the gastrointestinal contents of the maggots feeding on the remains.

The revelatory study, published in the Journal of Forensic Sciences, cites the case of an unidentifiable body found in the woods by Mexican police. It was suspected the body was that of a woman who had been abducted ten weeks earlier—her graduation ring was found near to the scene, however, the body was burned so badly it was impossible to collect any DNA samples from the damaged and deteriorated tissue.

It had already been suggested by other researchers that the gastrointestinal contents of maggots could be used to identify the subjects they feed on. However, never before has the theory been trialed in a legal, criminal case. Pathologists at Autonomous University of Nuevo León in San Nicolás, Mexico, led by María de Lourdes Chávez-Briones and Marta Ortega-Martínez, carried out short tandem repeat typing tests (a common method of DNA profiling) on the matter extracted from three dissected maggots found on the victim's face and neck, and separately on the alleged father of the missing woman. Preliminary results showed that the body was female, and the final outcome was a 99.685 percent probability of positive paternity—the victim had been identified.

Speaking to the New Scientist, Jeffrey Wells, a biologist at Florida International University who specializes in genotyping and insect evolution in relation to forensics, explained that the method could have plenty of practical applications, including identifying a victim through analysis of a maggot found in a vehicle transporting a body.

Maggots are already commonly used in criminal investigations to help police calculate time of death, particularly in bodies left to decompose for more than 72 hours. This is done by identifying the species of maggot infesting the corpse and working out how long that species has been alive by measuring it—shortly after death, blowflies and flesh flies are attracted to the body and lay larvae, which become maggots. By taking the maggots back to the lab and letting them grow to adulthood, thus ensuring the species has been correctly identified, police can get a pretty accurate timeline of events. One etymologist is even setting up a DNA sequence database so maggot species can be detected earlier.

Investigators are now catching up with research that has been ongoing in this area for some time now, recognizing the other potential practical benefits provided by corpse-loving insects. Pathologists are, for instance, also keen to use DNA extracted from hematophagous arthropods (blood-feeding insects) to identify corpses. In one study, adult crab lice removed from volunteers were frozen, air-dried and then profiled using the same methods designed for extracting mitochondrial DNA from human hair, teeth and bone. A comparison with DNA extracted from the volunteers' saliva showed the method could work in real-world cases, such as the one in Mexico. It can even be done with bed bugs. The stomach-churning possibilities of this burgeoning field seem to be wide open, and heralding in a new age of insect-aided criminal investigation.

You don't need to allege that the man was the woman's father unless identifying him as such disputes his claims or otherwise puts him in jeopardy. Perhaps, the "father of the allegedly missing woman" might be correct if cumbersome.

You don't need to allege that the man was the woman's father unless identifying him as such disputes his claims or otherwise puts him in jeopardy. Perhaps, the "father of the allegedly missing woman" might be correct if cumbersome.

It IS the alleged father. We know that a woman is missing so she would not be "allegedly missing". What we have here is an unidentified body who we are trying to tie to another person - the alleged father. If the DNA test failed to match the two, then obviously it wasn't the correct father and they would need to move on to another alleged father/mother/etc.

Actually, you should just delete the word "allegedly." You know which woman is missing, and you know the identify of the missing woman's father. There is nothing "alleged" about whether she is missing, and this is not a paternity case.

What you don't know is whether the body is that of the missing woman. So you might say the father of the alleged victim -- because we didn't know whether the missing woman was the victim or not.

I'm not understanding how if the body is too far gone to be able to get any reliable DNA, examining the stomach contents of maggots who are eating the too far gone body can somehow magically produce valid data. Seems like the contents would in turn also be too far gone.

I'm not understanding how if the body is too far gone to be able to get any reliable DNA, examining the stomach contents of maggots who are eating the too far gone body can somehow magically produce valid data. Seems like the contents would in turn also be too far gone.

It IS the alleged father. We know that a woman is missing so she would not be "allegedly missing". What we have here is an unidentified body who we are trying to tie to another person - the alleged father. If the DNA test failed to match the two, then obviously it wasn't the correct father and they would need to move on to another alleged father/mother/etc.

The allegation is not that he's a father. Therefore, one should never use "alleged" in that context. One might use the phrase "presumed father" since the assumption is that the body is that of his daughter. Seeing the word "alleged" led me to believe that somehow the paternity was in doubt, etc. and I expected to read details about it further on.

I'm not understanding how if the body is too far gone to be able to get any reliable DNA, examining the stomach contents of maggots who are eating the too far gone body can somehow magically produce valid data. Seems like the contents would in turn also be too far gone.

Can anyone shed some light?

Yeah, this is what we get for reading a Wired article instead of an Ars article..

If I had to guess though, the maggots are better at finding the soft squishy bits that are less damaged by the fire, and they also happen to consolidate a lot of those squishy bits inside themselves, where the dna can be extracted from.

But that's just a guess, since there are no details in the story (and I'm too lazy to click the links).

Edit: Technically, the paper abstract doesn't specifically state that the burns would have made standard DNA identification impossible, but it does state 'burned to badly to be identified'.. could be shorthand for 'identified via non-dna means'... without the full paper, it's hard to say.

On a serious note, and to gloss what two others have said already, how can a maggot contain DNA from human flesh if the DNA cannot be found in the flesh itself?

Because the maggots ate the flesh that contained the DNA and now it's only in the gut of the maggot.

That doesn't answer the question.

According to the article there was NO available DNA from the flesh because of fire damage. And had the maggots gotten to the body before it was burned, they, and the human DNA in their gut, would have been burned along with the body.*

So somehow maggots eating burned human flesh had a way of consuming DNA from the flesh. I would like to know if the maggot digestive system somehow acts as a filter or concentrator of DNA such that minute quantities of DNA in burned human flesh--quantities not extractable from the flesh itself--can be aggregated in the gut of the maggot. I think that is the most interesting question here.

*It's like encountering an empty pitcher of water next to a glass with some water in it and stating that the water from the pitcher is what is in the glass. How did it get there.

I'm not understanding how if the body is too far gone to be able to get any reliable DNA, examining the stomach contents of maggots who are eating the too far gone body can somehow magically produce valid data. Seems like the contents would in turn also be too far gone.

Can anyone shed some light?

Yeah, this is what we get for reading a Wired article instead of an Ars article..

If I had to guess though, the maggots are better at finding the soft squishy bits that are less damaged by the fire, and they also happen to consolidate a lot of those squishy bits inside themselves, where the dna can be extracted from.

But that's just a guess, since there are no details in the story (and I'm too lazy to click the links).

Edit: Technically, the paper abstract doesn't specifically state that the burns would have made standard DNA identification impossible, but it does state 'burned to badly to be identified'.. could be shorthand for 'identified via non-dna means'... without the full paper, it's hard to say.

It's nice to see people paying attention to the details like this, demonstrating true critical thought, unlike the article's author.

Well, apart from fiction shows, they did something similar in a case that was on Autopsy on HBO...which is a documentary series.

They didn't extract DNA from the maggots, but they found a corpse in a bathtub filled with water...actually, nothing else was left but the skeleton. But they scooped up the maggots still there and analysed them and found they were filled with barbiturates, which they concluded they person took a ton of to commit suicide.

That show was always pretty interesting, if somewhat gruesome, as they were all real cases.

On a serious note, and to gloss what two others have said already, how can a maggot contain DNA from human flesh if the DNA cannot be found in the flesh itself?

Because the maggots ate the flesh that contained the DNA and now it's only in the gut of the maggot.

That doesn't answer the question.

According to the article there was NO available DNA from the flesh because of fire damage. And had the maggots gotten to the body before it was burned, they, and the human DNA in their gut, would have been burned along with the body.*

So somehow maggots eating burned human flesh had a way of consuming DNA from the flesh. I would like to know if the maggot digestive system somehow acts as a filter or concentrator of DNA such that minute quantities of DNA in burned human flesh--quantities not extractable from the flesh itself--can be aggregated in the gut of the maggot. I think that is the most interesting question here.

*It's like encountering an empty pitcher of water next to a glass with some water in it and stating that the water from the pitcher is what is in the glass. How did it get there.

According to the article, the body was found burned, ten weeks after abduction.

I would assume that the body was not completely burned to the bone, rather some non-burned flesh remained. The non-burned flesh was mostly, if not all, consumed by maggots and/or deteriorated, leaving the burned flesh and bones left, thus not easily DNA testable.

Because the maggots had human DNA in them, and there was no other dead bodies in the area, the DNA most likely came from the body. Unless someone decided to move tens-to-hundreds of maggots from one dead body to another, which seems significantly less likely.